Discovery Chases Target After Releasing 3rd Satellite

August 30, 1985|By James Fisher of The Sentinel Staff

CAPE CANAVERAL — After flawlessly springing a satellite from Discovery's cargo bay, shuttle astronauts Thursday began scrambling to catch up with an ailing communications relay station that they hope to begin repairing Saturday.

A series of thruster firings put Discovery in a lower orbit and caused it to move faster than the satellite station. By Thursday night, the Leasat was about 3,000 miles ahead and the shuttle was gaining 55 miles with each orbit.

By Saturday morning, the shuttle will creep to within 35 feet, close enough for two spacewalking astronauts to snare the 14-foot-wide satellite and begin the repairs.

The Leasat, insured for $85 million, failed to activate after it was released from Discovery in April.

The repair work probably will be stretched over two days because of a malfunction in the robot arm's elbow joint that will slow it down by 75 percent, said flight director Jay Greene.

Thursday morning, crew members cleaned out the cargo bay by releasing a third satellite, a Leasat almost identical to the spacecraft they hope to repair. The satellite, also known as Syncom, was modified to prevent it from suffering the same malfunctions.

''Syncom's away,'' said astronaut James ''Ox'' van Hoften as the satellite flipped out of the cargo bay on its side like a Frisbee.

Mission control reminded spacewalker van Hoften, ''You'll get to wrestle with one just like that in a couple days.''

By afternoon, ground technicians reported that the satellite's booster engine had fired properly.

''We all really breathed a sigh of relief,'' said Marvin Mixon, vice president of Hughes Communications, which leases the satellites to the Navy for military communications. ''It's a wonderful day for all of us.''

As on Wednesday, crew members spent their free time Thursday looking out the window, admiring sunsets and providing spectacular television pictures of Hurricane Elena swirling in the Gulf of Mexico.

Today, astronauts will lower the cabin pressure and service their spacesuits in preparation for Saturday's work.

The arm's elbow malfunction requires astronaut John ''Mike'' Lounge to operate it with manual switches rather than using the computerized ''joystick.'' That takes longer, stretching the repair time estimate from 6 hours and 45 minutes to the current guess of 9 1/2 hours, Greene said.

Unless the repair work goes unusually fast, it most likely will be split over two days, he said. The Leasat would dangle on the robot arm overnight.

The second spacewalker is physician Bill Fisher, whose parents live in Winter Park. Discovery's commander is Joe Engle and its pilot is Richard Covey. If a second day's spacewalk is added, Discovery would make a rare landing before dawn Tuesday at Edwards Air Force Base in California. Otherwise, the shuttle would land in the daylight on Monday.